The present invention relates to an inflatable air bag cushion for use in covering a side portion of a vehicle interior adjacent to an occupant to be protected during a collision event, and more particularly, to an air bag cushion of substantially curtain-like structure for deployment away from the roof rail of the vehicle. The air bag cushion includes a main body portion for deployment generally downwardly and away from the vehicle roof rail to the side of an occupant to be protected and an inflatable upper portion for expansion between the head of the occupant to be protected and opposing portions of the roof rail structure.
It is well known in motor vehicles to provide air bag cushions for protecting a vehicle occupant. Such air bag cushions are typically in fluid communication with gas generating inflators so as to inflate the cushions upon sensing predetermined vehicle conditions such as decelerations exceeding a certain level. It is further known to provide air bag systems including inflatable restraint cushions which are deployed from positions of attachment to the vehicle frame along the roof rail portion of the vehicle frame so as to extend downwardly in substantially curtain-like fashion between an occupant to be protected and the side portion adjacent to such occupant. Such coverage is intended to provide cushioning restraint for the occupant during a side impact or extended roll-over collision event. Such curtain-like structures thereby provide protection to the vehicle occupant generally in regions below the location of attachment along the roof rail of the vehicle. That is, the protection afforded by such downwardly deployed curtain-like structures extends substantially in the region below the zone of attachment along the roof rail.
In some instances such as during an extended roll-over event, it is contemplated that an occupant may come into contact with the upper portions of the roof rail structure commonly referred to as the xe2x80x9cheaderxe2x80x9d portion of the roof rail. Typically, such contact will be between the head of the vehicle occupant and the header portion of the roof rail which is generally undesirable.
This invention provides advantages and alternatives over the prior art by providing an air bag cushion which is deployed from a location along the roof rail portion of a vehicle frame in substantially curtain-like fashion across the side of the vehicle interior over an expansive area adjacent to an occupant to be protected. The air bag cushion further includes an expansible upper portion expansible between the header portion of the roof rail and the head of an adjacently seated vehicle occupant. The main body portion and the inflatable upper portion of the air bag cushion are attachable to the roof rail structure along a common line of attachment. The inflatable upper portion and the main body portion of the air bag cushion may be inflated by a common source of inflation gas so as to utilize a single common inflator.
According to one potentially preferred aspect of the invention, the air bag cushion incorporates a substantially segmented construction along at least a portion of its length such that the inflatable upper portion and the main body portion are separated from one another except for a common inflation path adjacent a gas inlet opening to the air bag cushion. The segmented construction of the air bag cushion facilitates potentially desirable attachment arrangements between the air bag cushion and the roof rail so as to promote desired deployment characteristics for the inflatable upper portion which are substantially independent from the inflation and deployment of the main body portion.
According to another potentially preferred aspect of the present invention, deployment of the inflatable upper portion of the air bag cushion is not dependent upon inflation of the main body portion since inflation gas is not required to travel substantially through the main body portion before reaching the inflatable upper portion of the air bag cushion. The present invention thus provides a highly efficient and versatile structure for providing cushioning protection to a vehicle occupant and thus provides useful advantages over the prior art.